Installed the and tried out the the v5.15 kernel recently (pve-kernel-5.15.19-2-pve and pve-headers-5.15.19-2-pve). After installing the v5.15 kernel PCI passthrough stopped working even though on 5.13 it's working perfectly.
My config: PVE v7.1-10, Ryzen 3600, Asus B450-F (BIOS version 4602)...